Apparatus And Method For Sterilizing Endoscope

ABSTRACT

A method of sterilizing an article such as a flexible endoscope is performed in a sterilization chamber. A vacuum is applied in the sterilization chamber while the article is contained in the sterilization chamber. A sterilant is then introduced into the sterilization chamber. The pressure within the sterilization chamber is incrementally increased to provide a step-wise transition from a high vacuum state to atmospheric pressure. The article is thereby sterilized.

CROSS REFERENCE TO RELATED APPLICATION

The present application is a continuation of U.S. patent applicationSer. No. 16/225,035, filed on Dec. 19, 2018, now U.S. patent Ser. No.11/648,327, issued on May 16, 2023 which is a continuation of U.S.patent application Ser. No. 15/198,670, filed on Jun. 30, 2016, now U.S.patent Ser. No. 10/314,929, issued on Jun. 11, 2019, all of which isincorporated herein by reference.

BACKGROUND

Re-usable medical devices such as certain surgical instruments,endoscopes, etc., may be sterilized before re-use in order to minimizethe likelihood that a contaminated device might be used on a patient,which could cause an infection in the patient. Various sterilizationtechniques may be employed, such as steam, hydrogen peroxide, peraceticacid, and vapor phase sterilization, either with or without a gas plasmaand ethylene oxide (EtO). Each of these methods may depend to a certainextent on the diffusion rates of the sterilization fluids (e.g., gases)upon or into the medical devices to be sterilized.

Before sterilization, medical devices may be packaged within containersor pouches having a semi-permeable barrier that allows transmission ofthe sterilizing fluid—sometimes referred to as a sterilant—but preventsadmission of contaminating organisms, particularly post-sterilizationand until the package is opened by medical personnel. For thesterilization cycle to be efficacious, the contaminating organismswithin the package must be killed because any organisms that survive thesterilization cycle could multiply and re-contaminate the medicaldevice. Diffusion of the sterilant may be particularly problematic formedical devices that have diffusion-restricted spaces therein becausethese diffusion-restricted spaces may reduce the likelihood that asterilization cycle may be effective. For example, some endoscopes haveone or more long narrow lumens into which the sterilant must diffuse insufficient concentration for sufficient time to achieve a successfulsterilization cycle.

Sterilization of medical devices may be performed with an automatedsterilization system such as a STERRAD® System by Advanced SterilizationProducts of Irvine, California. Examples of automated sterilizationsystems are described in U.S. Pat. No. 6,939,519, entitled “Power Systemfor Sterilization Systems Employing Low Frequency Plasma,” issued Sep.6, 2005, the disclosure of which is incorporated by reference herein;U.S. Pat. No. 6,852,279, entitled “Sterilization withTemperature-Controlled Diffusion Path,” issued Feb. 8, 2005, thedisclosure of which is incorporated by reference herein; U.S. Pat. No.6,852,277, entitled “Sterilization System Employing a Switching ModuleAdapter to Pulsate the Low Frequency Power Applied to a Plasma,” issuedFeb. 8, 2005, the disclosure of which is incorporated by referenceherein; U.S. Pat. No. 6,447,719, entitled “Power System forSterilization Systems Employing Low Frequency Plasma,” issued Sep. 10,2002, the disclosure of which is incorporated by reference herein; andU.S. Provisional Pat. App. No. 62/316,722, entitled “System and Methodfor Sterilizing Medical Devices,” filed Apr. 1, 2016, the disclosure ofwhich is incorporated by reference herein.

Some sterilization systems may use vaporized chemical sterilants orchemical gas such as hydrogen peroxide, peracetic acid, ozone, chlorinedioxide, nitrogen dioxide, etc., to sterilize medical devices. Examplesof such systems are described in U.S. Pat. No. 6,365,102, entitled“Method of Enhanced Sterilization with Improved Material Compatibility,”issued Apr. 2, 2002, the disclosure of which is incorporated byreference herein, and U.S. Pat. No. 6,325,972, entitled “Apparatus andProcess for Concentrating a Liquid Sterilant and Sterilizing ArticlesTherewith,” issued Dec. 4, 2001, the disclosure of which is incorporatedby reference herein. Some such systems provide a hydrogen peroxide/gasplasma sterilization system comprising a vacuum chamber and plasmasource and increased concentration of hydrogen peroxide forsterilization. Some such systems may have difficulty sterilizing lumensof some medical devices if their length exceeds a certain value; or theprocessing time of such systems may still not be fast enough for someapplications. Thus, some medical devices such as long and/or narrowflexible endoscopes may not be completely sterilized by these systemsdue to the insufficient reach of sterilant vapor to the inside of thechannels. Such medical devices might therefore only be disinfectedwithout being sterilized. Sterilization systems that use ethylene oxidemay have a relatively long processing time (e.g., longer than 24 hours),which may be undesirable in some cases.

Operator error may result in medical devices that are erroneouslybelieved to be decontaminated being returned to service. Confirming thata sterilization cycle has been efficacious may help medical personnelavoid using a contaminated medical device on a patient. The sterilizedmedical device might not itself be checked for contaminating organismsbecause such an activity may introduce other contaminating organisms tothe medical device, thereby re-contaminating it. Thus, an indirect checkmay be performed using a sterilization indicator. A sterilizationindicator is a device that may be placed alongside or in proximity to amedical device being subject to a sterilization cycle, such that thesterilization indicator is subject to the same sterilization cycle asthe medical device. For instance, a biological indictor having apredetermined quantity of microorganisms may be placed into asterilization chamber alongside a medical device and subject to asterilization cycle. After the cycle is complete, the microorganisms inthe biological indicator may be cultured to determine whether any of themicroorganisms survived the cycle. The presence or absence of livingmicroorganisms in the biological indicator will indicate whether thesterilization cycle was effective.

While a variety of systems and methods have been made and used forsurgical instrument sterilization, it is believed that no one prior tothe inventor(s) has made or used the technology as described herein.

BRIEF DESCRIPTION OF THE DRAWINGS

It is believed the present invention will be better understood from thefollowing description of certain examples taken in conjunction with theaccompanying drawings, in which like reference numerals identify thesame elements and in which:

FIG. 1 depicts a schematic view of an exemplary medical devicesterilizing cabinet;

FIG. 2 depicts a high level flowchart of an exemplary set of steps thata sterilizing cabinet of the system of FIG. 1 could perform to sterilizea medical device;

FIG. 3 depicts a flowchart of an exemplary set of steps that may becarried out as part of a sterilization cycle within the set of steps ofFIG. 2 ;

FIG. 4 depicts a graph showing an exemplary plot of vacuum pressure in asterilization chamber of the sterilizing cabinet of FIG. 1 over timeduring performance of the sterilization cycle of FIG. 3 ;

FIG. 5 depicts a flowchart of an exemplary alternative set of steps thatmay be carried out as part of a sterilization cycle within the set ofsteps of FIG. 2 ; and

FIG. 6 depicts a graph showing another exemplary plot of vacuum pressurein a sterilization chamber of the sterilizing cabinet of FIG. 1 overtime during performance of the sterilization cycle of FIG. 5 .

DETAILED DESCRIPTION

The following description of certain examples of the technology shouldnot be used to limit its scope. Other examples, features, aspects,embodiments, and advantages of the technology will become apparent tothose skilled in the art from the following description, which is by wayof illustration, one of the best modes contemplated for carrying out thetechnology. As will be realized, the technology described herein iscapable of other different and obvious aspects, all without departingfrom the technology. Accordingly, the drawings and descriptions shouldbe regarded as illustrative in nature and not restrictive.

It is further understood that any one or more of the teachings,expressions, embodiments, examples, etc. described herein may becombined with any one or more of the other teachings, expressions,embodiments, examples, etc. that are described herein. Thefollowing-described teachings, expressions, embodiments, examples, etc.should therefore not be viewed in isolation relative to each other.Various suitable ways in which the teachings herein may be combined willbe readily apparent to those of ordinary skill in the art in view of theteachings herein. Such modifications and variations are intended to beincluded within the scope of the claims.

I. Overview of Exemplary Sterilization System

FIG. 1 depicts an exemplary sterilizing cabinet (150) that is operableto sterilize medical devices such as endoscopes, etc. Sterilizingcabinet (150) of the present example includes a sterilization chamber(152), which is configured to receive one or more medical devices forsterilization. While not shown, sterilizing cabinet (150) also includesa door that opens and closes sterilization chamber (152) in response toactuation of a kick plate. An operator may thereby open and closesterilization chamber (152) in a hands-free fashion. Of course, anyother suitable features may be used to provide selective access tosterilization chamber. Sterilizing cabinet (150) also includes asterilization module (156) that is operable to dispense a sterilant intosterilization chamber (152) in order to sterilize medical devicescontained in sterilization chamber (152). In the present example,sterilization module (156) is configured to receive replaceablesterilant cartridges (158) containing a certain amount of sterilant. Byway of example only, each sterilant cartridge (158) may contain enoughsterilant to perform five sterilization procedures.

Sterilizing cabinet (150) of the present example further includes atouch screen display (160). Touch screen display (160) is operable torender the various user interface display screens, such as thosedescribed in U.S. Provisional Pat. App. No. 62/316,722, the disclosureof which is incorporated by reference herein. Of course, touch screendisplay (160) may display various other screens as well. Touch screendisplay (160) is further configured to receive user input in the form ofthe user contacting touch screen display (160) in accordance withconventional touch screen technology. In addition, or in thealternative, sterilizing cabinet (150) may include various other kindsof user input features, including but not limited to buttons, keypads,keyboards, a mouse, a trackball, etc.

Sterilizing cabinet (150) of the present example further includes aprocessor (162), which is in communication with sterilization module(156) and with touch screen display (160). Processor (162) is operableto execute control algorithms to drive sterilization module (156) inaccordance with user input. Processor (162) is further operable toexecute instructions to display the various screens on touch screendisplay (160); and to process instructions received from a user viatouch screen display (160) (and/or via other user input features).Processor (162) is also in communication with various other componentsof sterilization cabinet (150) and is thereby operable to drive thosecomponents and/or process input and/or other data from those components.Various suitable components and configurations that may be used to formprocessor (162) will be apparent to those of ordinary skill in the artin view of the teachings herein.

Sterilizing cabinet (150) of the present example further includes anidentification tag reader (166), which is operable to read anidentification tag of a biological indicator as described herein. By wayof example only, identification tag reader (166) may comprise an opticalreader that is operable to read an optical identification tag (e.g.,barcode, QR code, etc.) of a biological indicator. In addition, or inthe alternative, identification tag reader (166) may comprise RFIDreader that is operable to read an RFID identification tag (e.g.,barcode, QR code, etc.) of a biological indicator. Various suitablecomponents and configurations that may be used to form identificationtag reader (166) will be apparent to those of ordinary skill in the artin view of the teachings herein. Data received through identificationtag reader (166) is processed through processor (162).

Sterilizing cabinet (150) of the present example further includes amemory (168), which is operable to store control logic and instructionsand that are executed by processor (162) to drive components such assterilization module (156), touch screen display (160), communicationmodule (154), and identification tag reader (166). Memory (168) may alsobe used to store results associated with setup of a sterilization cycle,performance of a load conditioning cycle, performance of a sterilizationcycle, and/or various other kinds of information. Various suitable formsthat memory (168) may take, as well as various ways in which memory(168) may be used, will be apparent to those of ordinary skill in theart in view of the teachings herein.

Sterilizing cabinet (150) of the present example further includes aprinter (170), which is operable to print information such as resultsassociated with setup of a sterilization cycle, performance of a loadconditioning cycle, performance of a sterilization cycle, and/or variousother kinds of information. By way of example only, printer (170) maycomprise a thermal printer, though of course any other suitable kind ofprinter may be used. Various suitable forms that printer (170) may take,as well as various ways in which printer (170) may be used, will beapparent to those of ordinary skill in the art in view of the teachingsherein. It should also be understood that printer (170) is merelyoptional and may be omitted in some versions.

Sterilizing cabinet (150) of the present example further includes avacuum source (180) and a venting valve (182). Vacuum source (180) is influid communication with sterilization chamber (152) and is also incommunication with processor (162). Thus, processor (162) is operable toselectively activate vacuum source (180) in accordance with one or morecontrol algorithms. When vacuum source (180) is activated, vacuum source(180) is operable to reduce the pressure within sterilization chamber(152) as will be described in greater detail below. Venting valve (182)is also in fluid communication with sterilization chamber (152). Inaddition, venting valve (182) is in communication with processor (162)such that processor (162) is operable to selectively activate ventingvalve (182) in accordance with one or more control algorithms. Whenventing valve (182) is activated, venting valve (182) is operable tovent sterilization chamber (152) to atmosphere as will be described ingreater detail below. Various suitable components that may be used toprovide vacuum source (180) and venting valve (182) will be apparent tothose of ordinary skill in the art in view of the teachings herein.

In addition to the foregoing, sterilizing cabinet (150) may beconfigured and operable in accordance with at least some of theteachings of U.S. Pat. No. 6,939,519, the disclosure of which isincorporated by reference herein; U.S. Pat. No. 6,852,279, thedisclosure of which is incorporated by reference herein; U.S. Pat. No.6,852,277, the disclosure of which is incorporated by reference herein;U.S. Pat. No. 6,447,719, the disclosure of which is incorporated byreference herein; U.S. Pat. No. 6,365,102, the disclosure of which isincorporated by reference herein; U.S. Pat. No. 6,325,972, thedisclosure of which is incorporated by reference herein; and/or U.S.Provisional Patent App. No. 62/316,722, the disclosure of which isincorporated by reference herein.

II. Overview of Exemplary Sterilization Process

FIG. 2 depicts a high level flowchart of an exemplary set of steps thatsterilizing cabinet (150) could perform to sterilize a used medicaldevice, such as an endoscope. Sterilizing cabinet (150) may beconfigured to perform one or more sterilization cycles, with differentsterilization cycles being appropriate for different types andquantities of medical devices. Thus, as an initial step, sterilizingcabinet (150) may display one or more available sterilization cycles viatouch screen display (160) and then receive a sterilization cycleselection (block 200) from the user.

Sterilizing cabinet (150) may also display instructions indicatingwhether a biological indicator should be used with the selectedsterilization cycle, and receive a biological indicator identification(block 202). Such a biological indicator identification (block 202) maybe provided via identification tag reader (166), via touch screendisplay (160), or otherwise. A biological indicator may be placed insidesterilization chamber (152) of sterilizing cabinet (150) before thesterilization cycle begins and may remain in the sterilization chamberduring the sterilization cycle. The user may thus identify theparticular biological indicator (block 202) before the biologicalindicator is placed in the sterilization chamber. The biologicalindicator may contain microorganisms that are responsive to a particularsterilization cycle. Upon completion of the sterilization cycle, thebiological indicator may be tested for the microorganisms in order toprovide a measure of the effectiveness of the sterilization cycle. Abiological indicator may not necessarily be required for allsterilization cycles, but may be required based on hospital rules orlocal regulations.

Selection of a sterilization cycle (block 200) and identification of abiological indicator (block 202) may define one or more requirements forthe configuration and arrangement of medical devices withinsterilization chamber (152). Thus, in order to provide preparation forthe sterilization cycle (204) once the sterilization cycle has beenselected (block 200) and the biological indicator has been identified(block 202), sterilizing cabinet (150) may provide a display via touchscreen display (160) indicating a proper medical device placement. Thisdisplay may serve as a visual guide to a user's placement of medicaldevice(s) (and perhaps a biological indicator) within sterilizingchamber (152) of sterilizing cabinet (150), based on the sterilizationcycle selection (block 200). A door of sterilization chamber (152) maybe opened to enable the user to place the medical device(s) (and perhapsa biological indicator) within sterilizing chamber (152) as instructed.

Once the user has placed the medical device in sterilizing chamber (152)based on these instructions, the user may press a start button or otherbutton indicating that medical device placement is complete. In someversions, sterilizing cabinet (150) is configured to automaticallyverify proper medical device placement. By way of example only,sterilizing cabinet (150) may employ photo sensors, imaging devices,weight sensors, and/or other components to verify proper medical deviceplacement in sterilizing chamber (152). It should be understood,however, that some versions of sterilizing cabinet (150) may lack thecapability of automatically verifying proper placement of a medicaldevice within sterilizing chamber (152).

If medical device placement is verified and/or the user has otherwisecompleted the cycle preparation (block 204), sterilizing cabinet (150)may start a load conditioning process (block 206). The load conditioningprocess (block 206) prepares sterilization chamber (152) and the medicaldevice(s) within sterilization chamber (152) for optimal sterilizationduring a sterilization cycle. Conditioning may include controlling andoptimizing one or more characteristics of sterilization chamber (152).For example, during load conditioning, sterilizing cabinet (150) maycontinuously monitor the level of moisture within sterilization chamber(152) while reducing the level of moisture by, for example, circulatingand dehumidifying the air of sterilization chamber (152), creating avacuum within sterilization chamber (152), heating sterilization chamber(152), and/or other methods for dehumidifying a sealed chamber. This maycontinue until sterilizing cabinet (150) determines that an acceptablelevel of moisture has been reached.

As part of the load conditioning cycle (block 206), sterilizing cabinet(150) may also continuously detect the temperature within sterilizationchamber (152) while heating sterilization chamber (152) by, for example,convection of heated air, conduction through an interior surface ofsterilization chamber (152), and/or using other techniques. This maycontinue until sterilizing cabinet (150) determines that an acceptableinternal temperature has been reached. Various conditioning actions suchas controlling temperature or humidity may be performed in parallel orin sequence. It should also be understood that the load conditioningcycle (block 206) may verify that the sterilization chamber is sealed;verifying contents of the sterilization chamber; checking physicalcharacteristics of the contents of the sterilization chamber such ascontent volume, content weight, or other characteristics; and/orperforming one or more conditioning steps that may include chemicaltreatment, plasma treatment, or other types of treatment to reducemoisture, raise temperature, and/or otherwise prepare the medicaldevices in sterilization chamber (152) for the sterilization cycle(block 208).

While the one or more conditioning actions are being performed as partof the load conditioning cycle (block 206), sterilizing cabinet (150)may display information via touch screen display (160) indicating to auser the duration of time before the sterilization cycle (block 208)performance may begin. Once all load conditioning criteria have beensuccessfully met, the load conditioning cycle (block 206) is complete,and the sterilization cycle (block 208) may then be performed. It shouldtherefore be understood that sterilizing cabinet (150) is configuredsuch that the sterilization cycle (block 208) is not actually initiateduntil after the load conditioning cycle (block 206) is complete. Itshould also be understood that the load conditioning cycle (block 206)may be omitted or varied in some versions of sterilizing cabinet (150)operation.

As noted above, sterilization cabinet (150) may begin performing thesterilization cycle (block 208) automatically and immediately after loadconditioning (block 206) has been completed. The sterilization cycle(block 208) may include exposing the medical device(s) in thesterilizing chamber to pressurized sterilant gas, further heattreatment, chemical treatment, plasma treatment, vacuum treatment,and/or other types of sterilization procedures. During performance ofthe sterilization cycle (block 208), sterilization cabinet (150) maydisplay information via touch screen display (160) such as a durationremaining for the sterilization cycle (block 208), the current stage ofthe sterilization cycle (block 208) (e.g. plasma, vacuum, injection,heat, chemical treatment), and/or other information.

In some versions, the sterilization cycle (block 208) includes theexemplary sub-steps shown in FIG. 3 . In particular, the cycle may beginwith a vacuum being applied (block 310) within sterilization chamber(152). In order to provide such a vacuum, processor (162) may activatevacuum source (180) in accordance with a control algorithm. Processor(162) will then determine (block 312) whether a sufficient pressurelevel has been reached within sterilization chamber (152). By way ofexample only, processor (162) may monitor data from one or more pressuresensors within sterilization chamber (152) as part of the determinationstep (block 312). Alternatively, processor (162) may simply activatevacuum source (180) for a predetermined time period and assume that theappropriate pressure has been reached in sterilization (152) based uponthe duration for which vacuum source (180) is activated. Other suitableways in which processor (162) may determine (block 312) whether asufficient pressure level has been reached within sterilization chamber(152) will be apparent to those of ordinary skill in the art in view ofthe teachings herein. Until the appropriate pressure level has beenreached within sterilization chamber (152), vacuum source (180) willremain activated.

Once sterilization chamber (152) reaches an appropriate pressure level(e.g., between approximately 0.2 torr and approximately 10 torr),processor (162) then activates sterilization module (156) to apply asterilant (block 314) in sterilization chamber (152). This stage of theprocess may be referred to as the “transfer phase.” By way of exampleonly, the sterilant may comprise a vapor of oxidizing agent such ashydrogen peroxide, peroxy acids (e.g. peracetic acid, performic acid,etc.), ozone, or a mixture thereof. Furthermore, the sterilant maycomprise chlorine dioxide. Various other suitable forms that thesterilant may take are described herein; while other forms will beapparent to those of ordinary skill in the art in view of the teachingsherein. It should also be understood that, in some versions, thesterilant may be applied (block 314) in different ways based on theuser's selection of cycle (block 200) as described above. Once thesterilant has been applied (block 314) to sterilization chamber (152),processor (162) monitors the time (block 316) to determine whether asufficient, predetermined duration has passed. By way of example only,this predetermined duration may be anywhere from a few seconds toseveral minutes. Until the predetermined duration has passed,sterilization chamber (152) remains in a sealed state at the above-notedpredetermined pressure level, with the applied sterilant acting upon themedical device(s) contained within sterilization chamber (152).

After the predetermined duration has passed, processor (162) activates(block 318) venting valve (182) to vent sterilization chamber (152) toatmosphere. In some versions, sterilization chamber (152) is allowed toreach atmospheric pressure, while in other versions sterilizationchamber (152) only reaches sub-atmospheric pressure. The venting stageof the process may be referred to as the “diffusion phase.” In thepresent example, the sterilization cycle is then complete (block 320)after completion of the diffusion phase. In some other instances, vacuumis again applied to sterilization chamber (152) after completion of thediffusion phase; and then a plasma is applied to sterilization chamber(152). It should be understood that the entire sterilization cycle shownin FIG. 3 (including the above-noted variation where a subsequent vacuumthen sterilization are applied) may be repeated one or more times afterbeing completed once. In other words, a medical device may remain withinsterilization chamber (152) and experience two or more iterations of theentire cycle shown in FIG. 3 (including the above-noted variation wherea subsequent vacuum then sterilization are applied). The number ofiterations may vary based on the cycle selection (block 200), which maybe influenced by the particular kind of medical device that is beingsterilized in sterilization chamber (152).

FIG. 4 depicts an exemplary plot (400) showing the pressure withinsterilization chamber (152) during performance of the sterilizationcycle (block 208) as depicted in FIG. 3 and as described above. As canbe seen, the pressure level drops significantly and suddenly when vacuumsource (180) is activated to apply vacuum (block 310) to sterilizationchamber (152). The pressure level then stays substantially constantwhile the sterilant is applied (block 314) and during the subsequent,predetermined duration (block 316). The pressure level then increasessignificantly and suddenly when venting valve (182) is activated (block318) to vent sterilization chamber (152) to atmosphere. Thus, in generalterms, plot (400) shows how the pressure within sterilization chamber(152) simply toggles between a single relatively high level (i.e.,atmospheric pressure) and a single relatively low level (i.e., a vacuumstate). An exemplary alternative sterilization cycle is described ingreater detail below with reference to FIGS. 5-6 .

Upon completion of the sterilization cycle (block 208), sterilizationcabinet (150) may cycle the results (block 210) of the sterilizationcycle (block 208). For instance, if the sterilization cycle (block 208)was canceled or unable to complete due to error or by a user action,sterilizing cabinet (150) may remain sealed and may also display asterilization cycle cancellation message via touch screen display (160);as well as various details relating to the sterilization cycle, such asdate, time, configuration, elapsed time, sterilization cycle operator,the stage at which the sterilization cycle failed, and other informationthat may be used to identify why the sterilization cycle. If thesterilization cycle (block 208) is completed successfully, sterilizationcabinet (150) may display a notification via touch screen display (160)indicating successful completion of the sterilization cycle (block 208).In addition, sterilization cabinet (150) may display information such assterilization cycle identifier, sterilization cycle type, start time,duration, operator, and other information (666).

In addition to the foregoing, sterilizing cabinet (150) may beconfigured to perform sterilization processes in accordance with atleast some of the teachings of U.S. Pat. No. 6,939,519, the disclosureof which is incorporated by reference herein; U.S. Pat. No. 6,852,279,the disclosure of which is incorporated by reference herein; U.S. Pat.No. 6,852,277, the disclosure of which is incorporated by referenceherein; U.S. Pat. No. 6,447,719, the disclosure of which is incorporatedby reference herein; U.S. Pat. No. 6,365,102, the disclosure of which isincorporated by reference herein; U.S. Pat. No. 6,325,972, thedisclosure of which is incorporated by reference herein; and/or U.S.Provisional Patent App. No. 62/316,722, the disclosure of which isincorporated by reference herein.

III. Exemplary Alternative Sterilization Cycle

As noted above, some versions of sterilizing cabinet (150) may havedifficulty effectively sterilizing medical devices such as flexibleendoscopes with relatively long, narrow lumens. For instance, someconventional sterilizing cabinets may be capable of sterilizing lumensthat are shorter than or equal to approximately 875 mm, with a lumendiameter of approximately 1 mm or larger. It may therefore be desirableto provide a modified sterilization cycle (block 208) that furtherpromotes effective sterilization of a medical device having one or morerelatively long, narrow lumens. A merely illustrative example of such amodified sterilization cycle is described in greater detail below. Byway of example only, a medical device having one or more relativelylong, narrow lumens may comprise a gastrointestinal endoscope that isbetween approximately 1 m long and approximately 3 m long, with a lumenhaving a diameter between approximately 0.5 mm and approximately 2.0 mm.It should nevertheless be understood that the process described belowmay also be performed on endoscopes having a length of at leastapproximately 500 mm or at least approximately 800 mm, with a lumenhaving a diameter less than approximately 6.0 mm.

FIG. 5 depicts an exemplary alternative set of sub-steps that may beperformed to provide the sterilization cycle (block 208) of sterilizingcabinet (150). In particular, the cycle may begin with a vacuum beingapplied (block 510) within sterilization chamber (152). In order toprovide such a vacuum, processor (162) may activate vacuum source (180)in accordance with a control algorithm. Processor (162) will thendetermine (block 512) whether a sufficient pressure level has beenreached within sterilization chamber (152). By way of example only,processor (162) may monitor data from one or more pressure sensorswithin sterilization chamber (152) as part of the determination step(block 512). Alternatively, processor (162) may simply activate vacuumsource (180) for a predetermined time period and assume that theappropriate pressure has been reached in sterilization (152) based uponthe duration for which vacuum source (180) is activated. Other suitableways in which processor (162) may determine (block 512) whether asufficient pressure level has been reached within sterilization chamber(152) will be apparent to those of ordinary skill in the art in view ofthe teachings herein. Until the appropriate pressure level has beenreached within sterilization chamber (152), vacuum source (180) willremain activated.

Once sterilization chamber (152) reaches an appropriate pressure level(e.g., between approximately 0.2 torr and approximately 10 torr),processor (162) then activates sterilization module (156) to apply asterilant (block 514) in sterilization chamber (152). By way of exampleonly, the sterilant may comprise a vapor of oxidizing agent such ashydrogen peroxide, peroxy acids (e.g. peracetic acid, performic acid,etc.), ozone, or a mixture thereof. Furthermore, the sterilant maycomprise chlorine dioxide or nitrogen dioxide. Various other suitableforms that the sterilant may take are described herein; while otherforms will be apparent to those of ordinary skill in the art in view ofthe teachings herein. It should also be understood that, in someversions, the sterilant may be applied (block 514) in different waysbased on the user's selection of cycle (block 200) as described above.Once the sterilant has been applied (block 514) to sterilization chamber(152), processor (162) monitors the time (block 516) to determinewhether a sufficient, predetermined duration has passed. By way ofexample only, this predetermined duration may be anywhere from a fewseconds to several minutes. Until the predetermined duration has passed,sterilization chamber (152) remains in a sealed state at the above-notedpredetermined pressure level, with the applied sterilant acting upon themedical device(s) contained within sterilization chamber (152). Thisstage of the process may be referred to as the “transfer phase.”

After the predetermined duration has passed, processor (162) activates(block 518) venting valve (182) to vent sterilization chamber (152) toatmosphere. With sterilization chamber (152) being vented (block 518) toatmosphere, processor (162) monitors the time (block 520) to determinewhether a sufficient, predetermined venting (block 518) duration haspassed. Until the predetermined venting (block 518) duration has passed,sterilization chamber (152) remains in a vented state. After thepredetermined venting (block 518) duration has passed, processor (162)determines (block 522) whether the sterilization cycle is complete.Examples of how this determination (block 522) may be made will bedescribed in greater detail below. It should be understood that, in thepresent example, the predetermined venting (block 518) duration may bevery brief. By way of example only, the predetermined venting (block518) duration may be approximately one second, two seconds, threeseconds, four seconds, five seconds, or any other suitable duration.

If processor (162) determines (block 522) that the sterilization cycleis complete, then the sterilization cycle is in fact complete (block528). However, if processor (162) determines (block 522) that thesterilization cycle is not yet complete, then processor (162) closesventing valve (182) to seal (block 524) sterilization chamber (152) at apressure level that is still less than atmospheric pressure. As notedabove, the venting (block 518) duration is very short in this example,such that the act of sealing (block 524) may occur very quickly afterventing (block 518) is initiated, assuming that the determinations(block 520, 522) confirm that sealing (block 524) is in order.

Sterilization chamber (152) will remain sealed (block 524) for a certainperiod of time. In particular, with sterilization chamber (152) beingsealed (block 524), processor (162) monitors the time (block 526) todetermine whether a sufficient, predetermined sealing (block 524)duration has passed. Until the predetermined sealing (block 524)duration has passed, sterilization chamber (152) remains in a sealedstate. After the predetermined sealing (block 524) duration has passed,processor (162) activates (block 518) venting valve (182) again to ventsterilization chamber (152) to atmosphere. By way of example only, thepredetermined sealing duration may be between approximately 5 secondsand 5 minutes, or more particularly between approximately 10 seconds andapproximately 2 minutes, or more particularly between approximately 20seconds and approximately 2 minutes.

At this point the process continues through the steps (blocks 518, 520,522, 524, 526) described above, such that the process provides a seriesof venting (block 518) and sealing (block 524) of sterilization chamber(152), allowing the pressure within sterilization chamber (152) toincrease in a stepwise fashion until sterilization chamber (152) reachesatmospheric pressure or some predetermined sub-atmospheric pressure.Again, each step of venting (block 518) is very brief in this example,such that the pressure of sterilization chamber (152) is held at levelsbelow atmospheric pressure during the acts of sealing (block 524) (e.g.,for a duration between approximately a few seconds or a few minutes). Byway of example only, until the final step of venting (block 518) isreached, each step of venting (block 518) may result in a respectiveincrease in the pressure within sterilization chamber (152) byapproximately 10 torr to approximately 100 torr, or more particularly byapproximately 10 torr to approximately 30 torr. Other suitable step-wisepressure increase values will be apparent to those of ordinary skill inthe art in view of the teachings herein. Once sterilization cabinet(150) reaches the end of the process, venting valve (182) remains opento allow sterilization chamber (152) to remain at atmospheric pressure.The final venting step (block 518) of the process may be referred to asthe “diffusion phase.”

In some versions, the venting duration (block 520) and/or the sealingduration (block 526) may vary. For instance, the venting duration (block520) and/or the sealing duration (block 526) may vary based on the cycleselection (block 200), which may be influenced by the particular kind ofmedical device that is being sterilized in sterilization chamber (152).In addition, or in the alternative, the venting duration (block 520)and/or the sealing duration (block 526) may vary based on where thesterilization cycle is at in the process (i.e., which venting (block518) iteration and/or which sealing (block 524) iteration). Varioussuitable ways in which the venting duration (block 520) and/or thesealing duration (block 526) may vary, and various bases upon which suchdurations may vary, will be apparent to those of ordinary skill in theart in view of the teachings herein.

FIG. 6 depicts an exemplary plot (600) showing the pressure withinsterilization chamber (152) during performance of the sterilizationcycle (block 208) as depicted in FIG. 5 and as described above. As canbe seen, the pressure level drops significantly and suddenly when vacuumsource (180) is activated to apply vacuum (block 510) to sterilizationchamber (152). The pressure level then stays substantially constantwhile the sterilant is applied (block 514) and during the subsequent,predetermined duration (block 516). The pressure level then increasesslightly when venting valve (182) is activated (block 518) to ventsterilization chamber (152) to atmosphere; yet stays at a level belowatmosphere when sterilization chamber (152) is sealed (block 524). Thepressure level then again increases slightly when venting valve (182) isagain activated (block 518) to vent sterilization chamber (152) toatmosphere; yet still stays at a level below atmosphere whensterilization chamber (152) is again sealed (block 524).

In the example shown in FIG. 6 , the cycle provides four iterations ofbrief venting (block 518), followed by four iterations of sealing (block524), before finally venting (block 518) fully to atmosphere. Thus, ingeneral terms, plot (600) shows how the pressure within sterilizationchamber (152) is increased in a step-wise fashion from a substantialvacuum state to atmospheric pressure. While FIG. 6 shows four iterationsof brief venting and brief sealing, other processes may employ any othersuitable number of iterations of brief venting and brief sealing. By wayof example only, variations may provide anywhere between two iterationsof brief venting and brief sealing and 100 iterations of brief ventingand brief sealing, or more particularly between two iterations of briefventing and brief sealing and ten iterations of brief venting and briefsealing, or more particularly between three iterations of brief ventingand brief sealing and seven iterations of brief venting and briefsealing.

In some instances, the process shown in FIGS. 5-6 may provide moreeffective sterilization of some medical devices as compared to thesterilization of the same medical devices using the process shown inFIGS. 3-4 . In particular, and without being limited by theory, thestep-wise venting of sterilization chamber (152) may provide agitationof the contents of sterilization chamber (152), which may assist indriving the sterilant into the lumen(s) and/or other internal spaceswithin the medical device. Moreover, and again without being limited bytheory, the step-wise venting of sterilization chamber (152) associatedwith the process shown in FIGS. 5-6 may provide convective mass transferof sterilant vapor molecules inside the lumen(s) and/or other internalspaces within the medical device; as compared to the simple diffusivemass transfer of vapor associated with the process shown in FIGS. 3-4 .Thus, when sterilization cabinet (150) performs the process shown inFIGS. 5-6 , sterilization cabinet (150) may sterilize a relatively longgastrointestinal endoscope (e.g., up to approximately 3 m in length andwith a lumen having a diameter up to approximately 1 mm); as compared tosterilization cabinet (150) performing the process shown in FIGS. 3-4 ,which would not be able to sterilize the long, narrow lumens of the samekind of gastrointestinal endoscope.

It should also be understood that the entire cycle shown in FIGS. 5-6may be repeated one or more times after being completed once. In otherwords, a medical device may remain within sterilization chamber (152)and experience two or more iterations of the entire cycle shown in FIGS.5-6 . The number of iterations may vary based on the cycle selection(block 200), which may be influenced by the particular kind of medicaldevice that is being sterilized in sterilization chamber (152).

By way of example only, an endoscope with a 3 m long lumen may be placedin sterilization chamber (152). Vacuum may be applied (block 510) toachieve a pressure level of approximately 4.5 torr in sterilizationchamber (152). Sterilant (e.g., approximately 1 mL of a hydrogenperoxide vapor at a concentration of 59%) may then be applied (block514) to provide a transfer phase lasting approximately 30 seconds.Sterilization chamber (152) may then be briefly vented (block 518) toachieve a pressure level of approximately 13.7 torr, and thensterilization chamber (152) may be sealed (block 524). Sterilizationchamber (152) may be held at the approximately 13.7 torr forapproximately 150 seconds. Sterilization chamber (152) may then bebriefly vented (block 518) again to achieve a pressure level ofapproximately 30.1 torr, and then sterilization chamber (152) may besealed (block 524) again. Sterilization chamber (152) may be held at theapproximately 30.1 torr for approximately 200 seconds. Sterilizationchamber (152) may then be briefly vented (block 518) again to achieve apressure level of approximately 47.1 torr, and then sterilizationchamber (152) may be sealed (block 524) again. Sterilization chamber(152) may be held at the approximately 47.1 torr for approximately 190seconds. Sterilization chamber (152) may then be briefly vented (block518) again to achieve a pressure level of approximately 760 torr (i.e.,atmospheric pressure), thereby providing a diffusion phase. Of course,the foregoing is just one merely illustrative example.

In some variations, before the final step of venting (block 518) isreached, additional sterilant is introduced into sterilization chamber(152) during one or more of the acts of stepwise venting (block 518).

Also in some variations, a pre-plasma may be applied in thesterilization cycle (block 208) to heat up the medical device containedin sterilization chamber (152). By way of example only, plasma may beapplied between applying a vacuum (block 510) and applying sterilant(block 514). In addition, or in the alternative, a post-plasma may beapplied at the end of the sterilization cycle (block 208) to degrade anyresidual sterilant that may be adsorbed to the surface of the medicaldevice contained in sterilization chamber (152). It should be understoodthat, before applying the post-plasma, a vacuum would first need to beapplied to sterilization chamber (152).

As noted above, the sterilant is applied (block 514) in the form of avapor within sterilization chamber (152). By way of example only,sterilization module (156) may comprise a combination of a vaporizer anda condenser. The vaporizer may include a chamber that receives aparticular concentration of sterilant solution (e.g., a liquid hydrogenperoxide solution with a concentration of approximately 59% nominal, orbetween approximately 58% and approximately 59.6%); where the sterilantsolution changes phase from liquid to vapor. The condenser may providecondensation of the sterilant solution vapor, and the concentration ofthe sterilant solution may be thereby increased (e.g., fromapproximately 59% nominal to somewhere between approximately 83% nominaland approximately 95% nominal), by removal of water vapor.Alternatively, any other suitable methods and components may be used toapply sterilant in the form of a vapor within sterilization chamber(152). In any case, to supplement the application of the sterilant inthe form of a vapor, the sterilant may also be applied (in liquid form)to the inside of lumen(s) and/or other internal spaces within themedical device and/or the outside of the medical device, before themedical device is placed in sterilization chamber (152). In suchversions, the sterilant may evaporate while vacuum is applied (block510) and even after vacuum is applied (block 510); and provide moreconcentration of sterilant to the areas of the medical device with lesspenetration range, thereby further promoting effective sterilization.

By way of example only, the process depicted in FIG. 5 may be carriedout at temperatures where the walls of sterilization chamber (152) arebetween approximately 30° C. and approximately 56° C., or moreparticularly between approximately 47° C. and approximately 56° C., oreven more particularly approximately 50° C.; and where the temperatureof the medical device in sterilization chamber (152) is betweenapproximately 5-10° C. and approximately 40-55° C.

While the foregoing examples are described in the context of sterilizingmedical devices, and particularly endoscopes, it should be understoodthat the teachings herein may also be readily applied in the context ofsterilizing various other kinds of articles. The teachings are notlimited to endoscopes or other medical devices. Other suitable articlesthat may be sterilized in accordance with the teachings herein will beapparent to those of ordinary skill in the art.

IV. Exemplary Combinations

The following examples relate to various non-exhaustive ways in whichthe teachings herein may be combined or applied. It should be understoodthat the following examples are not intended to restrict the coverage ofany claims that may be presented at any time in this application or insubsequent filings of this application. No disclaimer is intended. Thefollowing examples are being provided for nothing more than merelyillustrative purposes. It is contemplated that the various teachingsherein may be arranged and applied in numerous other ways. It is alsocontemplated that some variations may omit certain features referred toin the below examples. Therefore, none of the aspects or featuresreferred to below should be deemed critical unless otherwise explicitlyindicated as such at a later date by the inventors or by a successor ininterest to the inventors. If any claims are presented in thisapplication or in subsequent filings related to this application thatinclude additional features beyond those referred to below, thoseadditional features shall not be presumed to have been added for anyreason relating to patentability.

Example 1

A method of sterilizing an article, the method comprising: (a) receivingthe article in a sterilization chamber; (b) applying a vacuum to thesterilization chamber to reduce the pressure within the sterilizationchamber to a first pressure, wherein the first pressure is less thanatmospheric pressure; (c) introducing a sterilant into the sterilizationchamber; (d) maintaining the first pressure in the sterilization chamberfor a first period of time; (e) venting the sterilization chamber toincrease the pressure within the sterilization chamber to a secondpressure, wherein the second pressure is less than atmospheric pressure;(f) maintaining the second pressure in the sterilization chamber for asecond period of time; (g) venting the sterilization chamber to increasethe pressure within the sterilization chamber to a third pressure; and(h) maintaining the third pressure in the sterilization chamber for athird period of time.

Example 2

The method of Example 1, wherein the article comprises a medical device.

Example 3

The method of Example 2, wherein the medical device comprises anendoscope.

Example 4

The method of Example 3, wherein the endoscope defines a lumen.

Example 5

The method of Example 4, wherein the lumen has a length of at least 800mm and an inner diameter less than 6 mm.

Example 6

The method of any one or more of Examples 1 through 5, wherein thesecond period of time is longer than the first period of time.

Example 7

The method of any one or more of Examples 1 through 6, wherein the firstperiod of time is between approximately 5 seconds and approximately 5minutes.

Example 8

The method of any one or more of Examples 1 through 7, wherein the firstperiod of time is between approximately 20 seconds and approximately 2minutes.

Example 9

The method of any one or more of Examples 1 through 8, wherein thesecond pressure is between approximately 10 torr greater than the firstpressure and approximately 100 torr greater than the first pressure.

Example 10

The method of any one or more of Examples 1 through 9, wherein thesecond pressure is between approximately 10 torr greater than the firstpressure and approximately 30 torr greater than the first pressure.

Example 11

The method of any one or more of Examples 1 through 10, wherein thethird pressure is between approximately 10 torr greater than the secondpressure and approximately 100 torr greater than the second pressure.

Example 12

The method of any one or more of Examples 1 through 11, wherein thethird pressure is approximately 760 torr.

Example 13

The method of any one or more of Examples 1 through 12, furthercomprising applying a plasma to the sterilization chamber.

Example 14

The method of Example 13, wherein the act of applying a plasma comprisesapplying a plasma to the sterilization chamber between the act ofapplying the vacuum to the sterilization chamber and the act ofintroducing the sterilant to the sterilization chamber.

Example 15

The method of any one or more of Examples 13 through 14, wherein the actof applying a plasma comprises: (i) vacuuming the sterilization chamberafter maintaining the third pressure in the sterilization chamber, and(ii) then applying a plasma.

Example 16

The method of any one or more of Examples 1 through 15, furthercomprising introducing additional sterilant into the sterilizationchamber during the act of venting the sterilization chamber to increasethe pressure within the sterilization chamber to the second pressure.

Example 17

The method of any one or more of Examples 1 through 16, furthercomprising applying sterilant to one or more internal spaces within thearticle before receiving the article in a sterilization chamber.

Example 18

The method of any one or more of Examples 1 through 17, wherein thesterilant is selected from the group consisting of hydrogen peroxide,peroxy acids, ozone, or a mixture thereof.

Example 19

A method of sterilizing an article, the method comprising: (a) receivingthe article in a sterilization chamber; (b) applying a vacuum to thesterilization chamber to reduce the pressure within the sterilizationchamber below atmospheric pressure; (c) introducing a sterilant into thesterilization chamber; (d) venting the sterilization chamber toincrementally increase the pressure within the sterilization chamber,without reaching atmospheric pressure; (e) maintaining the incrementallyincreased pressure in the sterilization chamber for a period of time;(f) repeating steps (d) through (e) at least once; (g) venting thesterilization chamber to increase the pressure within the sterilizationchamber to atmospheric pressure.

Example 20

An apparatus, comprising: (a) a sterilization chamber, wherein thesterilization chamber is configured to receive a medical device; (b) avacuum source in fluid communication with the sterilization chamber; (c)a sterilant applying module in fluid communication with thesterilization chamber; (d) a venting valve in fluid communication withthe sterilization chamber, wherein the venting valve is further in fluidcommunication with atmosphere such that the venting valve is operable toselectively open and close a vent path between the sterilization chamberand atmosphere; and (e) a control module in communication with thevacuum source, wherein the control module is further in communicationwith the sterilant applying module, wherein the control module isfurther in communication with the venting valve, wherein the controlmodule contains a control logic configured to execute a sterilizingalgorithm such that the control logic is configured to: (i) activate thevacuum source to apply a vacuum to the sterilization chamber, (ii)activate the sterilant applying module to apply sterilant to thesterilization chamber, and (iii) selectively activate the venting valveto provide a step-wise incremental increase in pressure withinsterilization chamber toward atmospheric pressure.

V. Miscellaneous

It should be appreciated that any patent, publication, or otherdisclosure material, in whole or in part, that is said to beincorporated by reference herein is incorporated herein only to theextent that the incorporated material does not conflict with existingdefinitions, statements, or other disclosure material set forth in thisdisclosure. As such, and to the extent necessary, the disclosure asexplicitly set forth herein supersedes any conflicting materialincorporated herein by reference. Any material, or portion thereof, thatis said to be incorporated by reference herein, but which conflicts withexisting definitions, statements, or other disclosure material set forthherein will only be incorporated to the extent that no conflict arisesbetween that incorporated material and the existing disclosure material.

Having shown and described various embodiments of the present invention,further adaptations of the methods and systems described herein may beaccomplished by appropriate modifications by one of ordinary skill inthe art without departing from the scope of the present invention.Several of such potential modifications have been mentioned, and otherswill be apparent to those skilled in the art. For instance, theexamples, embodiments, geometrics, materials, dimensions, ratios, steps,and the like discussed above are illustrative and are not required.Accordingly, the scope of the present invention should be considered interms of the following claims and is understood not to be limited to thedetails of structure and operation shown and described in thespecification and drawings.

1. An apparatus, comprising: (a) a sterilization chamber, wherein thesterilization chamber is configured to receive a medical device; (b) avacuum source in fluid communication with the sterilization chamber; (c)a sterilant applying module in fluid communication with thesterilization chamber; (d) a venting valve in fluid communication withthe sterilization chamber and an atmosphere outside of the sterilizationchamber, the venting valve being operable to selectively open and closea vent path between the sterilization chamber and the atmosphere; and(e) a control module in communication with the vacuum source, thesterilant applying module, and the venting valve, wherein the controlmodule contains a control logic configured to execute a sterilizingalgorithm such that the control logic is configured to: (i) activate thevacuum source to apply a vacuum to the sterilization chamber, (ii)activate the sterilant applying module to apply sterilant to thesterilization chamber, and (iii) selectively activate the venting valveto provide a step-wise incremental increase in pressure withinsterilization chamber.
 2. A system comprising: the apparatus of claim 1;and the medical device.
 3. The system of claim 2, wherein the medicaldevice is an endoscope.
 4. The system of claim 2, wherein the medicaldevice is a plurality of endoscopes.
 5. The apparatus of claim 1,further comprising a door that opens and closes the sterilizationchamber in response to actuation of a kick plate.
 6. The apparatus ofclaim 1, wherein the sterilant applying module is configured to receivereplaceable sterilant cartridges containing a certain amount ofsterilant.
 7. The apparatus of claim 1, further comprising a touchscreen display configured to receive a user input.
 8. The apparatus ofclaim 7, wherein the touch screen display is operable to render varioususer interface display screens.
 9. The apparatus of claim 7, wherein thecontrol module is in communication with the sterilant applying moduleand the touch screen display and is operable to execute controlalgorithms to drive the sterilant applying module in accordance with theuser input.
 10. The apparatus of claim 1, further comprising anidentification tag reader operable to read an identification tag of abiological indicator.
 11. The apparatus of claim 10, wherein theidentification tag reader comprises an optical reader that is operableto read an optical identification tag of a biological indicator.
 12. Theapparatus of claim 10, wherein the identification tag reader comprisesan MD reader that is operable to read an RFID identification tag of abiological indicator.
 13. The apparatus of claim 10, wherein datareceived through the identification tag reader is processed through thecontrol module.
 14. The apparatus of claim 10, further comprising amemory operable to store control logic and instructions that areexecuted by the control module to drive components such as the sterilantapplying module, the communication module, and the identification tagreader.
 15. The apparatus of claim 14, wherein the memory is used tostore results associated with setup of a sterilization cycle,performance of a load conditioning cycle, and/or performance of asterilization cycle.
 16. The apparatus of claim 1, further comprising anoutput device operable to print information such as results associatedwith setup of a sterilization cycle, performance of a load conditioningcycle, and/or performance of a sterilization cycle.
 17. The apparatus ofclaim 16, wherein the output device is a printer.
 18. An apparatus,comprising: (a) a sterilization chamber; (b) a vacuum source in fluidcommunication with the sterilization chamber, the vacuum configured toapply a vacuum to the sterilization chamber; (c) a module having asterilant, the module being in fluid communication with thesterilization chamber to permit application of the sterilant to thesterilization chamber; and (d) a venting valve in fluid communicationwith the sterilization chamber and an atmosphere outside of thesterilization chamber, the venting being operable to selectively openand close a vent path between the sterilization chamber and theatmosphere to provide a step-wise incremental increase in pressurewithin sterilization chamber.
 19. A system comprising: the apparatus ofclaim 18; and a medical device.
 20. The system of claim 19, wherein themedical device is an endoscope or a plurality of endoscopes.